Understanding Risk

There are different types of risk in the health and medical fields. Knowing the basic types of risk can help you understand your chances of getting breast cancer and the steps you can take that may lower your risk.

Absolute risk

The most basic type of risk is absolute risk. Absolute risk is a person's chance of developing a certain disease over a certain period of time.

Absolute risk is estimated by:

Looking at a large group of people who are similar in some way (the same age, for example) and

Counting how many people in the group develop a certain disease over a certain period of time

Knowing the absolute risk of a disease can help you understand the health risks in your life.

Example of 1-year absolute risks

If we followed 100,000 women ages 30-34 for one year, about 25 women would develop breast cancer [2].

So, the 1-year absolute risk of breast cancer for a 30-34 year-old woman is 25 per 100,000 women (or 1 per 4,000 women). This risk is less than 1 percent.

This means the chances of getting breast cancer in the next year are less than 1 percent for the average 30-34 year-old woman.

This example shows the 1-year absolute risk of breast cancer for a young woman is low.

Examples of 10-year absolute risks

You may see absolute risk presented over long periods of time.

The table below shows the 10-year absolute risks of breast cancer by age. It shows the absolute risk of breast cancer is low in young women and higher in older women.